1. Field of Invention
The invention relates to an ink jet recording apparatus and a method for producing the same, and more particularly to an ink jet head unit and a method of producing the same.
2. Description of Related Art
An ink jet head recording apparatus performs printing by ejecting ink onto a sheet from nozzles provided in an ink jet head. The ink jet head includes a cavity plate having the nozzles, pressure chambers formed for the nozzles, and ink chambers, an actuator (a pressure generating portion) having driving elements associated with the pressure chambers, and a flexible flat cable sending an electrical signal to the actuator. The flexible flat cable, the actuator and the cavity plate are laminated one above the other.
The ink jet head communicates with an ink cartridge via ink supply passages formed in a body frame, and is adhesively secured to the body frame.
The ink jet head is covered with a cover plate so as to be protected against collision with recording sheets and to keep a connection between the actuator and the flexible flat cable free of foreign materials, such as ink and paper dust, to prevent an electrical short circuit from occurring. The cover plate is hermetically sealed around the ink jet head by the use of a sealer made of silicon. The cover plate has a window from which the nozzles protrude. The sealer is applied to the periphery of the window to prevent ink from spreading.
For example, U.S. Pat. No. 5,874,971 discloses an ink jet head that includes a nozzle case in which an ink jet head component having a nozzle is housed. The nozzle is connected to a cover head case. A groove is provided for forming a space between the ink jet head component and the cover head case. The nozzle case is provided with an adhesive injection opening to inject an adhesive from the injection opening into the groove. The area around the ink jet head is sealed by the adhesive and fastened to the case.
U.S. Pat. No. 4,994,825 discloses an ink jet head that includes an unevenly shaped groove or island at the bonding surface between the orifice plate and the head main body. The unevenly shaped groove or island buffers the stress generated due to curing shrinkage of the bonding agent or a difference in the thermal expansion coefficients between the respective constituent materials through the recessed portion constituting the space formed between the orifice plate and the head main body by the above uneven portion.
U.S. Pat. No. 6,079,810 discloses an ink jet head in which spaced circular holes, formed transversely through an orifice plate, and corresponding circular openings extending rearwardly into a body through its front end surface, are positioned in such that they are aligned with one another when the orifice plate is operatively secured to the front end of the body with adhesive, so that the holes and corresponding openings are filled with the adhesive.
It is desirable to increase a strength of bond in the above-described ink jet heads.
The invention provides an improved ink jet recording apparatus that comprises an ink jet head, a body frame, and a cover plate. The ink jet head has a plurality of nozzles that eject ink onto a recording medium, a plurality of pressure chambers provided in association with the nozzles, and a plurality of pressure generating portions that apply pressure to the pressure chambers so as to allow the ink to be ejected from the nozzles. The body frame communicates with an ink supply source and the ink jet head so as to supply the ink to the ink jet head. The cover plate has at least one window in a shape so as to enclose the nozzles. The cover plate is fixed to cover the ink jet head and fixed to the body frame. The ink jet recording apparatus further comprises an inlet that communicates with an internal space formed between the body frame and the cover plate and at least one outlet that communicates with the internal space. A filling material is supplied from the inlet and ejected to at least one outlet.